Printing head



R. L. JOHNSON PRINTING HEAD Feb. 4, 1964 2 seets-sneet 1 Filed Aug. 3l, 1961 INVENTOR. faq/ PH L Jam/50N Bytm Feb. 4, 1964 R. 1 JovHNsoN PRINTING HEAD 2 Sheets-Sheet 2 Filed Aug. 51. 1961 INVENTOR. RALPH L. Jam/50N BY ArTaA/EY United States Patent O 3,120,179 PRINTING HEAD Ralph L. Johnson, 4651 Sheila St., Los Angeles 22, Calif. Filed Aug. 31, 1961, Ser. No. 135,242 8 Claims. (Cl. 101-123) This invention relates to a printing head, particularly a head that holds a silk screen through which imprints are made on articles as the latter are successively moved into position beneath the screen.

An object of the present invention is to provide a silkscreen printing head that is adapted, especially, to imprint articles that are moved into printing position on a rotary indexing table and to so construct said head that components of the same may be moved to out-of-the-way positions during setup of the head relative to the rotary table and articles thereon.

Another object of the invention is to provide a silkscreen printing head that has a pigment-expressing component that is normally raised so that the article-supporting table may be freely indexed, is pneumatically moved down to printing position in relation to a silk screen and, then, through its pigment-expressing movement, and, nally, back to raised position during recovery movement back to its normally-retracted position, the head carrying out a printing and recovery cycle that is partly air-controlled and partly controlled by resilient bias that is exerted oppositely to the force of the air used in the operation.

A further object of the invention is to provide, in a printing head of the character above indicated, simple pigment-expressing means.

This invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combination and arrangements of parts, which will more fully appear in the course of the following description and which is based on the accompanying drawings. However, said drawings merely show, and the following description merely describes, one embodiment of the present invention, which is given by way of illustration or example only.

In the drawings, like reference characters designate similar parts in the several views.

FIG. l is a top plan view of a printing head according to the present invention, a portion of a rotary indexing article-supporting table being shown in operative relation to said head.

FIG. 2 is a broken side View of said head in the position thereof at the beginning of a printing cycle.

FlG. 3 is a vertical sectional view as taken on the plane of the line 3 3 of FIG. 1, with the head shown in a partly released position so the same may be moved clear of the top ot' the indexing table and articles thereon.

FIG. 4 is a cross-sectional View as taken on line 4-4 of FIG. 2.

FIG. 3 shows a support surface 5 that mounts the present printing head 6 md a rotary indexing table 7 in operative relationship so that articles 8, carried by said table, may receive pigment expressed through the interstices of a silk screen 9, of usual design, carried by said head 6.

Said table 7 forms no part of the present invention, typically comprising a horizontal member that, in usual Jays, receives and holds articles 8, in this case flat, or substantially dat, bottles, and is intermittently indexed on an axis 1t) by means suggested by a housing 11. The indexing direction is not material, providing the articles 3,120,179 Patented Feb. 4, 1964 rice 8 are brought successively into operative position beneath and in register with the silk screen 9.

When setting up the present means, particularly with respect to proper location of the articles on the table 7, improved facility of such preliminary work is provided for by the ability to move the means holding the screen 9 to an out-of-the-way position, as will later be described.

The printing head 6 comprises, generally, a standard 12 adapted to be ailixed to the surface 5, a head frame 13 carried by the standard, means 14 to vertically adjust the frame relative to the surface 5 and to articles 8 on table 7, a pivoted arm 15 for mounting the silk screen 9 and supported by frame 13 in printing position, a pivoted air motor 16 carried by said frame, a pigment-expressing squeegee 17 mounted directly on and movable by said motor, adjustable stop means 1 carried by the motor 16 to limit the position of the squeegee in one operative position thereof, resilient means 19 normally biasing the motor to an upwardly tipped position with the squeegee thereon upwardly spaced from the silk screen 9, releasable means 2li having stop engagement with the head frame 13 in the normal operative condition of the head and movable to release position when pivoted movement of the arm 15 is desired to move the screen 9 to a remote position relative to an article 8 therebeneath, and an air motor 21 iixedly mounted on the frame 13 and operable to engage the means 2t) to cause downward tipping of the motor 16, thereby moving the squeegee 17 into pigment-expressing engagement with the silk screen 9 The standard 12 is provided with a base plate 25 that is adapted to be bolted to the surface 5, and is formed to have a vertical slideway 26 for a slide 27.

The head frame 13 is xedly connected to said slide 27. The same is shown as comprising side walls 2S and 29 connected at one end by cross bars 311 and at the other end by an angle member 31.

The adjusting means 14 is shown as a lead screw 32 vertically disposed in the standard 12 and provided with a handle 33 The slide 27 constitutes a nut in threaded engagement with said screw so that rotation of the latter by means of its handle will raise or lower the frame 6 according to the direction of rotation of the handle. The adjustment is self-locking on the single-pitch lead screw shown.

The arm 15 is shown as comprising a pair of spaced levers 34 inward or" and parallel to the frame sides 23 and 29, a cross slide 35 connecting the forward ends of levers 34, and transversely spaced and forwardly directed support angles 36 adjustably carried by said cross slide so that the transverse spacing thereof may be varied ac cording to the transverse dimension of the screen 9 that is supported by said support angles 36 The rearward ends of levers 34 are connected to a pivot rod 37 that extends between frame walls 28 and 29 so that said frame 6 is freely gravitationally supported by engagement of levers 34 with the frame cross member 31 as is shown best in FIGS. 3 and 4. It will be clear that the arm 15 may be lifted on pivot rod 37 to space the support angles 36 an appreciable distance above an article S therebeneath, as hereinbefore explained.

The air motor 16 is shown as comprising a cylinder 33 mounted, by means of an ear 39, on an adjusting pivot screw 40 extending between the frame walls 2S and 29 above the pivot rod 37. Said motor cylinder is provided with end air inlets 41 and 42 to propel the inner piston thereof in either direction depending on which inlet receives operating air. Said piston is suggested by a rod 43 that extends forwardly from cylinder 3S. Thus, the squeegee 17 that is carried on the end of the piston rod, is directly moved pneumatically back and forth by the motor 16. Transverse adjustment of the motor and its squeegee, according to the transverse adjustment of the screen-mounting angles 36, may be locked by a nut 44 on the Vpivot screw 40.

The squeegee 17 may be of conventional design and is here shown as a mounting plate 45 rotationally carried on the end of piston rod 43, a squeegee blade 46 on the end of plate 45, and a clamp bar 47 to affix said blade to said plate. The lower transverse edge of blade 46 is adapted to contact the screen 9 and to achieve automatic full edge engagement with said screen because of the free rotational mount of plate 45 on rod 43.

The stop means 13 comprises a bracket 4S afnxed to the forward end of cylinder 33, a threaded stud 49 extending forwardly from said bracket above and parallel to the piston rod 43, a stop nut 50 threadedly adjustable along stud 49, and a buer washer 51 lining said nut and interposed between said nut and the plate 45 of the squeegee. lSaid means 18 is designed to stop or limit the retracted position of the squeegee, i.e., the position thereof at the staat of a pigment-expressing operation. Nn limit means i is needed for the end of said operation since the projection of rod 43 will be stopped when the piston in cylinder 3S reaches its most forward position. Y

The means 19 for upwardly tipping the motor 16 on its pivot, so that the squeegee is clear of the silk screenr9, is shown as a tubular housing 52 affixed to the angle member 31 and vertically disposed so that a plunger 53 extending from the upper end of said housing is adapted to impinge on the lower edge of an arm 54 that parallels the motor 16 and is connected thereto by the bracket 48 so as to pivotally tip around pivot screw 4t) with said motor. An expansion spring 55 in housing 52 resiliently biases said plunger outwardly, thereby upwardly tipping arm 54 and the motor 16 that is connected to said arm.

The means 20 limits such upward tipping of the motor and is here shown as an arm 56 on a pivot 57 on arm 54, and provided with a pad 57a that is normally held by said spring 55 in engagement with the under face of a projection 58 on the anglemember 31. Said arm 56 hasV a hook shape or C form vthat naturally assumes hooking engagement with projection 58, as in FIG. 2, retaining the motor 16 at the slight upwardly tipped position of said figure.

A handle 59 on arm 56 may be used to retract the same to the position of FIG. 3, thereby freeing the motor 16 so the same may be tipped further upwardly to the position of the latter ligure. Thus, the screen-mounting arm 6 is now free to also be upwardly tipped for the reasons hereinbefore given.

The air motor 21 comprises a vertical cylinder 6i) with an air inlet 61, said cylinder being xedly connected to the mentioned fixed projection 58. A piston 62 in cylinder 60 has a stem 63 that extends downwardly through projection 58 and Vinto engagement with the pad 57a on the arm 56. As a consequence, upon admission of pressure air to inlet 61, the stem 63 is projected from projection 58 and, by engaging the pad 57a, tips the motor 'downward to the dot-dash position of FIG. 3V in which the squeegee is inthe 'starting position.

With-the parts in the latter position, air is admitted to inlet 42, causing the squeegee to wipe over the screen 9 andexpress liquid pigment, placed on said screen in the usual manner, through the screen interstices. After the squeegee'has made its printing pass over the screen, air to inlet 61 is -shut off and the cylinder vented, allowing the means. 19i to extend and upwardly tip the motor and squeegee. Thereafter, air to inlet 41 is shut olf and admitted to inlet V42, causing retraction of the piston rod 43 With/the squeegee thereon, the motor 16 now having its initial slightly upwardly tipped posi ion, as in FIG. 2.

Any suitable means, such as clamp members 64 and thumb nuts 65, may be used to clamp the screen 9 in position to span between the angles 36.

The control means for synchronizing the air iow to inlets 41, 42 and 61 is not shown since the same may be accomplished in many ways, For instance, valved lines 4 leading to the respective inlets may have their valves operated by cams or the like in the described sequence and in synchrony with the indexing means of the table 7.

The resilient biasing means 19 may comprise air acting on the plunger 53 instead of the expansion spring 55.

While the foregoing has illustrated and described what is now contemplated to be the best mode of carrying out the invention, the constluction is, of course, subject to modification without departing from the spirit and scope of the invention. Therefore, it is not desired to restrict the invention to the particular form of construction illustrated and described, but to cover all modicrations that may fall within the scope ofthe appended claims.

Having thus described this invention, what is claimed and desired to be secured by Letters Patent is:

1. A printing head comprising a fixed frame, a silkscreen-holding arm pivotally connected at one end to said frame, said frame having a support portion engaging the arm and holding the same in operative position, an air motor pivotally connected to said frame provided with an air-projectible and air-retraetible piston rod extending above and over a silk screen mounted on said arm, a pigment-expressing squeegee on the end of said rod, means to resiliently bias the motor to a normal operating position tipped upwardly on its pivot to space the squeegee above the silkscreen, hook means to limit the upwardly tipped position of the motor to said operating position, and air-controlled means carried by the frame and engaged with the hook means to draw the motor down from its tipped position to a position with the squeegee thereon in pigment-expressing engagement Y with the silk screen.

-ed on said arm, a pigment-expressing squeegee on the end of said rod, means to resiliently bias the motor Yto a normal operating position tipped upwardly on its pivot to space the squeegee above the silk screen, hook means to limit the upwardly tipped position of the motor to said operating position, air-controlled means movable along an axis carried by the frame and engaged with the hook means to draw the motor down from its tipped position to a position with the squeegee thereon in pigment-expressing engagement with the silk screen, and a pivot mounting the hook means and on which the latter means is movable to non-hooking position to release the motor for pivotal movement above its normal tipped position and freeing the pivoted screen-holding arm for similar upward pivotal movementfaway from'the'support portion of the frame.

3. A printing head according to claim 2 provided with means to mount the head relative to articles to be imprinted by pigment expressed through the silk screen, and means to adjust the head on said mount according to the position of said article.

4. A printing head according to claim 2 in which the axis of said rod of the motor while in printing position intersects the axis of the air-controlled means, thereby 6. In a silk-screen printing head, an elongated airoperated motor comprising a cylinder and a pistonrod extending from an end of the cylinder, a pivot mounting the other end of the cylinder, resilient means biasing the motor to an upwardly tipped position, a pigment-expressing squeegee on the end of the piston rod held spaced from a silk screen by said resilient means, releasable means t0 limit said tipped position to an operating position, and air-operated means to move the motor on its pivot in a direction opposed to the bias of said resilient means to draw the squeegee into pigment-expressing engagement with the silk screen.

7. In a silk-screen printing head according to claim 6, pivoted means to mount said screen, and means to release the releasable means to free bot'n the motor and the screen-mounting pivoted means for upward movement on their respective pivots.

8. In a silk-screen printing head according to claim 7,

said motor being provided with opposite operating-air inlets to reciprocate the piston rod and the squeegee thereon, and means carried by the cylinder of said motor to limit said reciprocation in one direction.

References Cited in the le of this patent UNITED STATES PATENTS 

6. IN A SILK-SCREEN PRINTING HEAD, AN ELONGATED AIROPERATED MOTOR COMPRISING A CYLINDER AND A PISTON ROD EXTENDING FROM AN END OF THE CYLINDER, A PIVOT MOUNTING THE OTHER END OF THE CYLINDER, RESILIENT MEANS BIASING THE MOTOR TO AN UPWARDLY TIPPED POSITION, A PIGMENT-EXPRESSING SQUEEGEE ON THE END OF THE PISTON ROD HELD SPACED FROM A SILK SCREEN BY SAID RESILIENT MEANS, RELEASABLE MEANS TO LIMIT SAID TIPPED POSITION TO AN OPERATING POSITION, AND AIR-OPERATED MEANS TO MOVE THE MOTOR ON ITS PIVOT IN A DIRECTION OPPOSED TO THE BIAS OF SAID RESILIENT MEANS TO DRAW THE SQUEEGEE INTO PIGMENT-EXPRESSING ENGAGEMENT WITH THE SILK SCREEN. 